1. Field of the Invention
The invention relates to computer-aided implantation of artificial joint components and, more particularly, to a plate probe and associated system and method used with a surgical navigation system during artificial joint implantation and associated operations that require osteotomy.
2. Description of the Invention Background
Currently, over 200,000 total hip replacement (THR) and over 250,000 total knee replacement (TKR) operations are performed annually in the United States alone. Many of these operations are repeat procedures to correct errors in alignment of the implant and the limb associated with the joint involved in the operation. Such errors lead to accelerated implant wear, early prosthesis loosening and sub-optimal clinical function. Although existing mechanical alignment guides have improved the precision of arthroplasty or joint replacement, errors in implant and limb alignment continue to occur.
Recently computer-assisted surgical systems and techniques have been developed to address the shortcomings of the purely mechanical surgical techniques. U.S. Pat. No. 6,002,859 discloses a computer-assisted system and method for facilitating the implantation of an artificial component in a joint. This system includes a computer, associated software and a tracking device. A computer model of the joint and a model of the artificial component are prepared pre-operatively. The tracking device collects positional data through point probes, i.e. probes that come in contact with a point. The tracking device determines the coordinates of the physical point, such as a point on the patient""s body, with which the probe is placed in contact, thus creating a reference point. The system identifies the position of the component within the joint model. Using the data collected from the tracking device, the system aligns the joint model with the actual joint and the component model with the actual component.
During arthroplasty, damaged parts of joint bone must be removed and remodeled to allow a prosthetic component to fit in connection to the joint. It is desirable to accurately determine the orientation of planned planar cuts of the bones of a joint and to verify the orientation of the planar cut after the surgical cut has been performed. Determining such orientation by using a point probe or other mechanical alignment guides is an indirect procedure, which is still prone to error.
There remains, therefore, a need for an improved system and probe that can be used to measure and track the orientation of planar surfaces during computer-assisted surgical operations involved in arthroplasty.
The invention meets the identified needs, as well as other needs, as will be more fully understood following a review of this specification and drawings.
One embodiment of the invention discloses a probe for facilitating the orientation of an osteotomy, i.e. a bone cut. The probe comprises a coupler and a plate. The coupler is configured so that it can be connected to a position tracker, such that the position and orientation of the plate can be determined from the position of the tracker. The plate is configured so that it can be inserted into an opening of a guide which is generally designed for receiving and guiding a surgical saw blade during a cutting operation.
In another embodiment, the probe and a position tracker may be included in a system, which further includes a computer system comprising a pre-operative geometric planner and a pre-operative kinematic biomechanical simulator in communication with the preoperative geometric planner. The pre-operative kinematic biomechanical simulator outputs a position for implantation of the artificial component and a position and orientation of the osteotomy.
The invention also includes a method for facilitating the implantation of an artificial component during arthroplastic surgery that requires a planar osteotomy. The method includes creating a model of a joint and a model of an artificial component for implantation in the joint. The method further includes calculating a range of motion based on a simulated movement of the joint with the artificial component in a test position, determining the desired implant position based on the calculated range of motion and a predetermined range of motion and aligning the model of the joint with the joint and the model of the artificial component with the artificial component. The method also includes tracking the desired position of the artificial component and the joint, modeling the plane of the osteotomy, and tracking the plane of the osteotomy.
The invention also includes a method of facilitating a planar osteotomy on a joint during surgery. The method comprises positioning a bone-cutting guide on a portion of the joint prior to the osteotomy, attaching a probe having a planar portion to a position tracker and inserting the planar portion into an opening in the bone-cutting guide. The method also includes verifying and correcting the orientation of the plane of the osteotomy before performing the osteotomy, and may also include verifying the orientation of the plane of the osteotomy after performing the osteotomy.
Other features and advantages of the invention will become apparent from the detailed description of the embodiments set forth herein and from the appended claims.